Genetic predisposition to changes in neurochemical processes may result in variations of normal behavior or appear as mental disorder, e.g., Parkinson's disease or Huntington's disease. In the CB6R1 genetic analytical system (9 mouse strains and various crosses) we will measure the level of ACTH and Beta-endorphin, by radioimmunoassay of plasma, pituitary and different brain regions; the rapidity of their degradation in the presence of brain extracts of different strains; and properties of opiate receptors (concentration, affinity and distribution). The data will be subjected to genetic analysis and correlated to heritable stress-induced behavior patterns, found in recent preliminary experiments.